In the arts of assembly and construction shims constitute a well-known expedient for adjusting the placement and orientation of doors, windows and the like. However, the use of shims is not confined to the mounting of doors and windows. Rather, any fixture to be installed and oriented (leveled) within an aperture in a structure benefits from the use of shims.
A very common use of shims is in the building industry, where shims are conventionally constituted by wooden wedges. These are fit into spaces as needed to properly square the fixture that is being mounted within a structure frame. A shim (or plurality of shims) is normally forced (often using impact) into a space between the structure frame and the fixture until the correct leveling and orientation is achieved. Afterwards, those parts of the shim that stick out beyond the frame in which the fixture is mounted are broken off.
Traditionally, shims have been made of wood. Very often, they are simply scraps of wood that are collected at the convenience of the builders, and used wherever they would fit. Unfortunately, the collection of appropriate scraps has resulted in lost time, as has the on-site manufacturer shims from scrap pieces of wood. This is often awkward, especially if those mounting the structure within the frame are not particularly skilled.
Consequently, pre-manufactured wooden shims are often purchased as a matter of convenience to save the valuable time of the workers who are mounting the fixture. One well-known type of wooden shim is mass-produced to a general size of approximately nine inches long by approximately two inches wide. These are generally made of varying thicknesses from ¼ inch up to ½ inch thick. Normally the cross section is configured as a wedge since this is the best shape for forcing the shim into a space until the proper squaring of the structure is achieved. After the fixture is properly positioned in the frame through the use of shims, any parts of the shim extended beyond the frame are broken off.
There are a number of drawbacks with traditional wooden shims. Either they have to be purchased, or they have to be salvaged from scraps on a job site. One difficulty with wood is that it can be splintered relatively easily, especially if subject to substantial duress. This is usually present on a job site where the wooden shim has often been splintered from a larger piece of wood, forced into a space (usually through impact), and then splintered again when mounting screws or nails are driven through it. All of this disruption might easily degrade the wooden shim until it is no longer fit for its original purpose. The wood itself is also vulnerable to the environment since it is relatively porous. As a result, the wood tends to compress or expand if force is applied to it. This is especially true if the wood is subjected to moisture, even just that in the surrounding air. Wood does decay or degrade over time, especially when subjected to a wide range of environmental situations.
Alternatives to wood have also proven to be somewhat expensive due to material and fabrication costs. However, there have been attempts to use plastic wedges as shims. Such devices are discussed in U.S. Pat. Nos. 6,155,004; 5,953,862; and, 5,853,838. All these patents are incorporated by reference as demonstrating the advantages of using plastic as a shimming material.
Plastic shims are easily configured to accommodate fracture lines and screw holes, thereby overcoming one of the chief disadvantages of wooden shims. However, in size and shape, the plastic shims of the aforementioned patents are the same as wooden shims, an elongated wedge. Consequently, it is usually necessary to use multiple plastic shims in the same manner of using wooden shims. The use of multiple plastic shims also mean that screw holes may no longer align, and that fracture lines may not be as convenient as they are for a single shim. Likewise, multiple shims means that a mass of plastic is now compressed to fill the space. This may provide some difficulty with the use of nails or screws that must be driven through the mass of plastic.
The necessity of having a large number of shims means that a great deal more construction debris will be added to any job site. Further, the standard on-site disposal of debris, burning, may not always be suitable for plastic debris.
Consequently, a more convenient and less wasteful technique for shimming would be highly desirable. The new technique should be simple to use, even for the unskilled, and require as few pieces as possible. The new system would also admit to creating reduced construction waste or debris.